John B. Buse, M.D., Ph.D., of the University of North Carolina School of Medicine in Chapel Hill, and colleagues conducted a study involving 3,980 sixth graders from the HEALTHY study cohort in an effort to characterize glycemic abnormalities, specifically including hrA1C, defined as 5.7 to 6.4 percent, and IFG, defined as 100 to 125 mg/dL.

At baseline, the researchers found that 3.2 percent had hrA1C and 16.0 percent had IFG. Children with hrA1C were more likely to be black, have a family history of diabetes, and have higher body mass index (BMI), waist circumference, and fasting insulin levels, compared with those with A1C <5.7 percent. IFG was more likely in Hispanic children and those with increased BMI, waist circumference, and fasting insulin as well as those with high blood pressure and higher mean triglycerides, compared to those with fasting plasma glucose <100 mg/dL. Compared with children with IFG, those with hrA1C had a higher BMI in sixth grade, which persisted to eighth grade.

"In the HEALTHY cohort, the fasting plasma glucose and A1C tests identify two different high-risk populations. The IFG population is five times as large and less likely to persist with glycemic abnormalities but more hypertensive and more dyslipidemic," the authors write. "Arguably, these features suggest a population where there may be a benefit of intervention and follow-up to prevent cardiovascular risk."